


Dirty Little Secret

by dejiko001



Category: Demashitaa! Powerpuff Girls Z
Genre: Aged-Up Character(s), Alternate Universe - Post-Canon, Consensual Sex, Cross-Posted on FanFiction.Net, Cunnilingus, Established Relationship, F/M, Lemon, Oral Sex, Romance, Secret Relationship, Smut, Vaginal Fingering, Vaginal Sex
Language: English
Status: Completed
Published: 2021-03-13
Updated: 2021-03-13
Packaged: 2021-03-22 02:14:03
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,058
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/30031458
Author URL: https://archiveofourown.org/users/dejiko001/pseuds/dejiko001
Summary: The PPGZ and RRBZ had been enemies since they were young and continued to act that way during their fights. Unbeknownst to the public, they were all dating each other: Brick and Momoko, Boomer and Miyako, and Butch and Kaoru.In Butch and Kaoru's case, their dirty little secret from the public involved a lot more than just kissing.One-shot: Greenz.
Relationships: Butch (PPG)/Matsubara Kaoru | Powered Buttercup
Kudos: 3





	Dirty Little Secret

**Author's Note:**

> **Disclaimer:** I don't own the anime/manga of _Demashitaa! Powerpuff Girls Z_ nor its characters used in this fanfic.
> 
>  **A/N:** Wow, I never thought the day that I'd post a lemon—or smut, as some people would call it nowadays—would come. (No pun intended.)
> 
> I blame the pandemic. I've been deprived of RGB content, and I needed a bit more joy in my life, which contributed to me finishing this one-shot.
> 
> To be honest, I had written the first draft of this one-shot back in 2016 with it (slightly) NSFW. I wound up revisiting it in 2017, making it full-blown erotica. And now, here I am, in 2021, during a pandemic, posting this one-shot after expanding the erotica and adding _some_ plot before it.
> 
> I had debated throughout the years before I joined AO3 in 2020 whether I should post this one-shot. It was originally going to stay hidden from the world because FFN doesn't allow explicit content. I had this fear that I'd get this one-shot taken down or, worse, I'd get suspended from FFN—which I've seen in other fandoms. After I found out that AO3 allows explicit content, including sexual content, that's when the gears started turning in my head that I could _maybe_ post this one-shot, after all.
> 
> This one-shot takes place post-canon, many years after the end of the anime when the PPGZ and RRBZ are young adults. And for the record, yes, the title of this one-shot is inspired by The All-American Rejects' _Dirty Little Secret_. I think listening to this song a lot back then and during this pandemic contributed to this one-shot, too.
> 
> With all that said, I hope this brings some joy as it did with me. Enjoy!

It had always been like this for as long as Buttercup could remember—the way that she and Butch would be at each other's throats, Brick and Blossom would have their cold stare-downs that thickened the tension in the atmosphere, and Boomer and Bubbles would have their respective share of mockery and sneak attacks.

She, Blossom, and Bubbles were 21 now. It was unimaginable that, to this day, the Powerpuff Girls Z would still be active as superheroines. All the supervillains had retired—although Mojo Jojo would occasionally have his antics—but the only ones who would cause trouble were the Rowdyruff Boys Z.

It became complicated when their age suddenly sped up without any explanation. One day, they appeared like the 13-year-olds they were when she, Blossom, and Bubbles were 16, and over a year, they suddenly became older—their voices rougher and huskier, their thought processes and behavior very much different from when they were 13. The only conclusion was that they became 17-year-old teenagers.

Buttercup never knew how much Butch could get on her nerves until then.

Before, he had been just a simple annoying brat who she could mock and easily beat, especially since she was still taller than him at that time—just as Blossom and Bubbles could do with the others—but now, he towered over her figure. Her mockery of what happened in the past no longer fazed him and instead incited him to make innuendos. The aggressive tension between them only grew whenever she happened to encounter him in public as her civilian, everyday self because the Rowdyruffs had found out long, long ago who the girls were when they had stolen their uniforms and cross-dressed as them, therefore stealing their identities and tricking everyone in the city.

And now, here she was, her back against the cement ground in the tiny crater that he had sent her flying into. She looked up at a 22-year-old Butch, who had been stretching way above in the sky.

"Hey, come on!" Butch yelled. "I know you can do _way_ better than that."

Buttercup swiftly flew up, her uniform dirtied from the debris of the impact, and she made eye contact with him.

So much had changed over the years between the Powerpuff Girls Z and Rowdyruff Boys Z—between _them_.

"So, round two?" Butch asked, breaking her out of her thoughts, and he winked, sending a smirk that she knew was meant to rile her up.

Buttercup clicked her tongue. "Shut up."

* * *

Kaoru felt like crashing onto the couch. Her body felt sore all over, thanks to Butch not holding back. She could still recall the adrenaline she felt from their fight. Once the cooldown period kicked in, she finally realized how much she had ached.

"Babe, you look like you're about to pass out."

Kaoru had somehow subconsciously laid down on the couch. Her memory already felt fuzzy. Thankfully, her hearing was clear as ever because she still recognized that voice when she heard it—not that she could ever forget it.

"Babe?"

"Whose fault do you think that is?" Kaoru weakly retorted as she shut her eyes. She just wanted sleep to overcome her already, and it was only when she felt a hand caress her cheek that she opened her eyes again.

Butch's dark green eyes were easy to get lost in. Despite how dark they were, she could see how reflective they were. Over the years, she grew to notice the types of emotions Butch had with just a single glance. Sometimes, the way he looked at her would send a shiver down her spine—even now.

"Well, I would assume it's because of college," Butch replied, a smirk on his lips.

Kaoru couldn't help but smile when she noticed how his eyes had softened and felt his hand travel down to her shoulder.

"Hey, at least we're both graduating this year."

"True."

There was a long pause of silence, which was weird for Kaoru because she noticed how he had a faraway gaze in his eyes. It was unlike him—not unless he was deep in thought about something, and it was only around her that he ever let his walls down and revealed this side of him to her.

"What's wrong?" Kaoru asked, already sitting up.

"Babe, if you're tired, you can rest on the couch," Butch replied, caressing her cheek again. "I can carry you to your bed later."

Kaoru narrowed her eyes. "Don't change the subject. What were you thinking about?"

Butch looked at her for a few seconds before closing the distance between them.

Kaoru had already shut her eyes, just as he did, when his lips made contact with hers.

The way that he kissed her—from back when they were first together when it was short, brief, and perhaps chaste until it grew to more, heavy, fulfilling, and filled with _want_ and _need_ —always left her breathless and her heart pounding in her chest.

She felt his lips move against hers slowly, even the way that his tongue brushed against her lips, and she shuddered when she felt his hand move underneath her shirt. She managed to pull away, just enough to get him to stop before she knew it'd escalate—not that she ever minded—but she could feel the want in her body grow as she felt his fingers brush against her bare skin.

"Butch, at least tell me what's bothering you," Kaoru whispered, her eyes now open as she stared at him. She was aware how close they still were—his nose right against hers—and she hoped that he didn't notice how her breathing hitched when his hand traveled upward.

"Nothing's bothering me," Butch whispered back, his gaze soft. "I just felt thankful. That's all."

"For?"

"That you're in my life. That you helped push me to become better, even when we were, you know, frenemies."

"Before or after we stopped being at each other's throats?"

"Just when we started talking in general." Butch paused. "Also, if you want me to choke you—"

" _Butch._ "

Butch laughed.

Kaoru felt her cheeks—and maybe even ears—warm, especially with how attractive his laughter sounded.

"You know I'm dead serious, right?"

Kaoru then quickly smacked him on the arm, and she was now aware of how flushed she probably appeared to him because his laughter came back tenfold. "God, shut up, will you? Freaking pervert."

"Says the gorgeous girl in front of me." Butch paused again, this time his smile dropping. "Don't you think the public should know? About us? And your friends and my brothers?"

Kaoru blinked in surprise, and seconds later, she frowned. "I don't know… We all talked about this as a team already, remember? Both Brick and Momoko made the call."

"Yeah, but do you know how much it sucks that I can't even _touch_ you in public?" Butch whined. "Can't even kiss you on the cheek."

Kaoru laughed. "That's why you come over in the evenings and spend the night."

"You know, you do a pretty badass job at pulling off the act."

"Yeah, well, that's because you pissed me off a lot over the years."

"Can't help it because it's my only excuse to even get to interact with you in public." Butch paused, frowning. "Still, we're all older now. I don't see the point in keeping up with the personas and act."

Kaoru frowned as well. "You three are still seen as villains, even if you're lying low nowadays—at least in the eyes of the citizens who've been here much longer."

Butch scoffed. "Don't remind me, babe."

Kaoru's frown grew, her face softening. "Another place rejected you?"

"Yeah." Butch let out a long sigh. "I kind of get why the whole secret identity thing is so appealing now. Makes it convenient for stuff like this." Butch paused again. "It'd be a lot easier for us to go out with each other, too."

"Yeah…"

"It'd be easier for me to grab that ass of yours, too."

Kaoru tried to smack him on the arm again, but instead, he caught her arm and, with ease due to his superhuman strength, lifted her from the couch. She tried every ounce to not scream from the sudden gesture, and seconds later, she suddenly realized that the way he had been carrying her wasn't that of him throwing her over his shoulder—which whenever he did on the battlefield, it was to sneak a grope on her ass, and she'd have to hit him with her hammer as a reminder that he _wasn't_ supposed to do that—but that he was holding her up via her ass, and she held onto him with her arms around his neck. Instinctively fearing that she'd fall because he was the type of jerk to prank her, she wrapped her legs around his hips.

It was then that she felt something against her shorts—the yoga shorts that she knew Butch liked—that her heartbeat started picking up again and she felt her desire accumulating. When their gazes met, especially when he smirked, she felt her desire increase further upon seeing how lustful his gaze became.

"Bedroom?" Butch whispered.

"Yeah," Kaoru whispered back, her legs wrapping around his hips tighter.

Kaoru felt the movement and watched everything around her move, the wait only making her desire increase further—until finally, she saw her bedroom door close, heard it lock, and felt herself getting placed onto her bed.

Butch hovered over her, brushing a few strands from her face, still close with her as Kaoru loosened her grip around his hips, letting her legs rest against the bed. "I won't hold back."

Kaoru let out a laugh. "You didn't hold back earlier from our fight."

"Yeah, I guess I'll be making another part of you sore, won't I?"

"I don't know," Kaoru teased. "Will you?"

Butch smirked, his gaze becoming even more sultry and lustful than before. "Challenge accepted."

Before Kaoru knew it, articles of her clothes began to slide off her body, leaving her to wear only her black cotton panties. Everywhere she felt Butch's fingers brush against her skin, her breathing hitched, craving more of his touch.

Finally, his hands roamed slowly around her half-naked body before he lied on top of her and began to suck on her neck. The way she gave him access so easily, the way she arched her back and neck, everything about it made him want her more, and the harder he sucked, the softer and louder she moaned. When she started to whimper and grip his shirt tightly, he felt his nether region grow with want.

She shivered when he pulled his lips away. "Ah… Butch…" She whimpered again.

He stared at the large hickey on her neck, and he went to suck on another spot.

She gasped, and her legs wrapped around his hips. As he sucked harder, she began to squirm and whimper loudly.

His hands started to roam around her naked thighs, and he heard her moan as his fingers traced the edges of her panties.

She let out a small gasp as he began to rub her nether region through her panties.

Butch relished the fact that she shuddered when his fingers brushed near her clitoris, and he lifted his head to look at her properly. "Did you wear these for me?"

"I didn't wear it for you," she snapped, but she said it so weakly. Another moan escaped from her mouth when he kissed her neck.

"Uh-huh, like you would wear sexy panties like these every day."

She grunted in response as she glared at him.

"I wouldn't glare at me if I were you."

She glared at him harder.

He raised an eyebrow, and at once, he brought his mouth above her right nipple.

Her eyes widened. "Butch— _ah!_ "

He licked it slowly in a teasing manner, and he watched how Kaoru closed her eyes and continued to moan softly; it was only when he began to suck on it and closed his eyes that Kaoru's moans grew louder.

"Ah… Ah, _ah!_ "

Butch let his free hand grab the other breast, allowing his fingers to play with the nipple. He listened to her growing moans as her legs clamped tightly around his body.

"Ah, ah! _Butch!_ "

Finally, he let go of her nipple, and he heard her whimper as her moans finally quieted down. He looked at her and sent her a small smirk as she sent him a weak, but very cute glare at him.

"I'm going to kill you," Kaoru growled weakly.

"Uh-huh," he retorted huskily before one of his hands pinched her nipples.

Kaoru yelped.

"Like you can do anything to me in this position."

Kaoru sent him a hard glare at that.

"If you keep glaring at me, I'm going to do worse things to you," he replied cheekily.

Of course, Kaoru continued to glare at him, almost daring him to continue.

With a wolfish grin, he pulled down her panties, which made Kaoru gasp, and tossed them aside.

"Hey!" Kaoru exclaimed.

Butch ignored her cry, spread her legs apart, and brushed one of his fingers along her folds. When he heard her breathing hitch, he sent her another smirk and sang, "Someone's dripping wet."

"Shut up," Kaoru growled.

"I guess someone must've missed me, huh?"

"I did _not_ miss you."

"Oh, yeah?"

Kaoru growled in response.

"Wrong answer, babe."

Before Kaoru could even reply, Butch had already lied down and began to lick her folds before his mouth finally settled on her clit, continuously licking it.

"Ah! Butch!"

His tongue licked against her dripping folds again and again until finally, he went to her vaginal opening, and he inserted his tongue. At that point, he felt her hands comb through his hair as she moaned in complete bliss when he took his tongue out and licked her clitoris again.

"Oh, _God._ "

He licked her continuously until she finally began to tug at his hair, making him realize that she was close—so very close. He heard her moans grew louder.

"Fuck! I'm coming!"

And Butch continued licking, even during her shuddering orgasm, and he heard her whimper.

"No, _please_ , no, Butch."

Butch didn't listen. Instead, he licked up the juices around her vagina and her clitoris, making Kaoru shudder and moan.

"Oh, _God_."

Butch lifted his head, wiping his face with the back of his hand, and stared at Kaoru, who was panting and whose face was completely flushed. He hovered over her face and kissed her on the lips deeply as he started to rub her clit slowly, but repeatedly in a circular motion. He watched her squirm underneath him as she tried to clamp her legs together, but failed because his body was in the way.

Kaoru pulled her face away from him, now clutching onto his shoulders. "Ah, _ah!_ "

"Come on, babe, come for me again," he whispered huskily.

Kaoru squirmed at hearing that as her face flushed even more.

" _Come_ ," Butch demanded, narrowing his eyes as he finally inserted a finger into her opening.

" _Ah!_ " Kaoru exclaimed before she felt him pumping his finger in and out of her vagina. "Oh, oh, _God_."

"Yeah, you like that, don't you?" Butch purred, his smirk growing.

"Oh, oh, oh, _fuck_ ," Kaoru moaned, feeling his finger entering and leaving each time she moaned.

Butch relished how Kaoru's moans filled the room, echoing off the walls as he continued to pump his finger in and out of her vagina. Then, he inserted a second finger.

Kaoru's eyes grew wide as her mouth opened. " _Oh_ —"

Butch began pumping both fingers before he sucked on her left nipple.

"Oh, _fuck!_ " Kaoru exclaimed, feeling pleasure throughout her body. "Fuck me, fuck me, fuck me! Oh, _yes!_ "

The slopping sounds of her juices filled the room as Kaoru moaned loudly, and when Butch sucked harder on her nipple, she screamed.

"Oh, God!" Kaoru moaned. "Don't stop, _please!_ "

At that point, Butch let go of her nipple and took out his fingers. When he saw her glare at him weakly, practically pouting, he smirked as he went to move to be between her legs once more. "Don't glare at me like that, babe. You're going to love this. Trust me."

Kaoru's face flushed red when he winked at her, and when he began licking her clitoris again, Kaoru moaned before her hands instinctively reached for his head, combing her fingers through his hair. "Oh, God…"

Then, he inserted a finger into her vagina.

"Oh, God!"

Immediately, as Butch licked her clitoris, he began pumping his finger in and out, just as fast as he was going earlier.

"Oh, oh, _shit!_ " Kaoru screamed as she tugged on Butch's hair.

He continued to suck and lick her juices, relishing the way she screamed and cursed, and it gave him all the more reason to pump his finger even faster.

"Oh, fuck, fuck, fuck!" Kaoru moaned before her mouth formed a large O. "Oh, _God_ , yes, fuck me, fuck me, fuck me, fuck me, _fuck me!_ "

The feeling of Butch licking her clitoris and his finger pumping in and out of her vagina was just too much for Kaoru, making her scream and moan louder with every passing second.

"Yes, yes, yes, ooh, _yes!_ " Kaoru moaned, feeling herself get turned on even more as she heard Butch loudly slurp the juices before going back to her clitoris. " _Oh!_ "

Butch pumped his finger even faster, even harder as he began licking her clitoris violently.

"Ooh, yes! I'm coming! I'm coming, I'm coming, _I'm coming!_ "

A wave of euphoria erupted throughout Kaoru's body, and she shuddered when she felt Butch pull out his finger. As Kaoru slowly came down from that pleasurable euphoria, she felt Butch lick the remaining juices and then her clitoris, and she moaned. "No, please, don't…"

Butch finally lifted his head to look at her, and he smirked. "Says the girl who told me to not stop."

"Fuck you."

Butch raised his eyebrow in amusement. "Gladly. Just give me a moment."

Kaoru opened her mouth to say something, but decided to stay silent as he got up to his dresser. She tried to move or even get up, but her legs kept shaking as a result of her orgasm, and she mentally cursed. However, she felt herself get even more turned on as she watched Butch strip in front of her eyes.

The way he slid his t-shirt off over his head revealed his back and stomach muscles. She'd never admit it to Butch, but his physical features were just too damn attractive. Soon enough, he was down to just his boxers, and she blinked when he turned around with a condom packet in his hand.

"Ready, babe?" he asked, smirking.

Kaoru blushed before she looked away, not even responding.

Butch chuckled in amusement as he took off his boxers and put on the condom. He moved back to the bed, grinning at how Kaoru was still looking away from him.

Honestly, the pout on her face was just too damn cute.

Kaoru finally turned her head to look at him, and she glared at him, but the blush on her face was apparent. "I should kill you."

"You mean fuck me, right?" Butch replied cheekily as he spread her legs again. He couldn't help but grin in amusement when he noticed that her legs were shaking from her orgasm.

"Shut up."

Butch shrugged as he lifted her legs above his shoulders. "Okay."

Within an instant, he thrust into her.

Kaoru's mouth dropped into a large O, and her head dropped back onto the pillow.

"Oh, fuck," Butch whispered huskily before he began thrusting in and out.

Kaoru reached up, her hands grabbing onto his arms, and she looked at his face. "Oh, God, Butch…"

At that point, Butch thrust faster.

"Ah! _Butch!_ "

Soon enough, Kaoru's loud moans, Butch's grunts, and the slapping sounds of their nether regions filled the entire room.

"You're always so _tight_ for me," Butch whispered, the sweat appearing on his body as he continued to thrust.

Kaoru tried to reply, but she screamed when she felt him hit a certain spot.

Butch knew immediately at that point that he found her g-spot, so he quickly started thrusting at that angle.

"Oh, oh, God, Butch, Butch, _Butch!_ " Kaoru screamed before she orgasmed for the umpteenth time, but her moans continued as he continued to thrust into her. "Oh, oh, yes, fuck me, please, please, _please!_ "

The feeling of him going in and out of her overwhelmed Kaoru once more as she shut her eyes while grabbing onto Butch's arms tightly. Finally, she opened her eyes to look at Butch straight in the eyes, and her mouth formed another large O as his thrusts became faster.

"Fuck…" Butch muttered huskily.

At that moment, Kaoru orgasmed once more, and as she rode out that wave of euphoria, she watched Butch look at her in such a lustful way. It sent shivers down her spine as his thrusts slowly came to a halt, but he didn't leave her body.

Butch put down her legs before leaning forward and then kissing Kaoru deeply. After their lips parted, he gave her a quick peck on the cheek as he let her catch her breath before he went to her ear. "I'm not done yet. You know that, right?"

Kaoru shuddered as her arms wrapped around his neck while her legs wrapped around his hips.

Butch then backed away, allowing Kaoru to still be able to hold onto him, and he began thrusting again, but slowly this time.

Kaoru moaned softly as her legs tightened around his hips.

Butch began thrusting again, much faster than before.

Kaoru's mouth dropped to form an O again. "Oh, God…" She threw her head back when she felt Butch hit her g-spot again. "Oh, God! Butch!"

Butch's pants became louder as Kaoru continued to moan, and when his thrusts grew faster, Butch kissed Kaoru to muffle her scream. Kaoru wrapped her arms around his neck, but it wasn't long before they both parted for air.

Finally, Butch let out a long moan while Kaoru let out a scream as they both orgasmed. They panted heavily, each trying to catch their breath before Butch kissed Kaoru once more on the lips.

Kaoru moaned softly, and when he pulled away, she yawned.

Butch chuckled. "Tired?"

Kaoru grunted, glaring at him.

Butch chuckled again as he slowly pulled out and stood up. He took off the condom and whistled when he saw the amount. "Damn."

"What is it?" Kaoru asked.

Butch turned around to show Kaoru the amount of semen in the condom. "This is how much you've deprived me, babe."

"We had sex just three days ago," Kaoru deadpanned.

Butch snorted as he threw away the condom into a trash can before putting on his boxers. "Three days is a long time."

Kaoru rolled her eyes, but smiled. "You're an idiot."

Butch then crawled back into bed, hovering over Kaoru before he pulled the large blanket over both of their bodies. He then leaned in, allowing his lips to brush against hers. "And _you're_ drop-dead sexy and gorgeous."

Kaoru blushed, and just then, she yawned.

Butch chuckled before he gave her a quick peck on the cheek and rolled over to her side. He wrapped his arms around Kaoru after both of them readjusted themselves, allowing him to spoon her, and he buried his head into the crook of her neck, kissing it gently.

A few seconds later, Kaoru groaned before sitting up, the blanket still draped around her body. " _Right._ Almost forgot that I need to go pee and wash up."

" _Or_ we could just sleep since the sex was _so_ good that you're tired?"

"Hey, I don't want a UTI," Kaoru deadpanned. "Besides, you got to wash up, too."

"Does this mean shower sex?"

Kaoru let out a groan, but she couldn't resist the growing smile on her face, especially when she noticed his loving gaze mixed with his cheeky grin.

Even if no one could know about their relationship, Kaoru was okay with that—at least, until it was safe to reveal to the public. For now, it'd be their dirty little secret.


End file.
